Self Tutoring



By Jim Thompson

I had a process engineer working for me at one time who was assigned to redesign a stock cleaning system. This had all happened before I came on board and the system was installed when I arrived. It didn't work. The pumps seemed to be too small and the system could just not get the through-put it needed. After much investigation, it turned out he had not taken elevation changes into his piping system design. And there were many elevation changes. I am sure he knew better, but had forgotten.

Today, your excuses are over. Any project or process engineer can get a quick review of engineering principles with AI. Look what happened when I asked ChatGPT "How do I learn to size piping systems?"

This was the answer:

That’s a great question — sizing piping systems is one of the most practical and valuable engineering skills you can develop, especially if you’re working with steam, condensate, air, water, or chemical systems (as in paper manufacturing, HVAC, or process industries).

Here’s a structured way to learn it effectively:



🧭 1. Understand What "Sizing" Means

Piping sizing means selecting:

• Pipe diameter that gives acceptable pressure drop and velocity
• Material and wall thickness for the pressure rating
• Layout (fittings, valves, elevations) for hydraulic performance and cost

You’re balancing pressure loss, flow velocity, cost, and system reliability.

📚 2. Learn the Key Fundamentals

Start with the basic physics and equations that govern flow in pipes:

• Continuity equation:
• Q=V×AQ = V \times AQ=V×A
• (Flow rate = velocity × area)
• Bernoulli’s equation: Energy conservation in a flowing fluid
• Darcy–Weisbach equation:
• hf=fLDV22gh_f = f \frac{L}{D} \frac{V^2}{2g}hf​=fDL​2gV2​
• (Head loss = friction factor × (length/diameter) × velocity² / 2g)
• Friction factor (f): From the Moody chart or Colebrook–White equation
• Minor losses: Valves, fittings, bends — expressed as equivalent length or K-factors

💧 3. Study Recommended Velocity Ranges

Each fluid type has typical velocity limits to prevent erosion, water hammer, and noise:

FluidRecommended Velocity RangeSteam20–100 ft/s (depends on pressure and dryness)Condensate3–6 ft/sWater3–10 ft/sCompressed air20–60 ft/sSlurries3–10 ft/s (to prevent settling)

You’ll often start with velocity, then check pressure drop.

⚙️ 4. Learn to Use Sizing Charts and Software

Professional designers rarely do all calculations by hand. Common tools:

• Crane TP-410: Flow of Fluids Through Valves, Fittings, and Pipe (industry classic)
• ASHRAE Handbook (for HVAC and chilled water)
• API 14E, ISO 5167, and ISA standards (for oil & gas and industrial piping)
• Software:
• AFT Fathom / Arrow
• Pipe Flow Expert / FluidFlow
• EES or Excel (for simpler systems)

🧩 5. Practice Step-by-Step

Start with small exercises:

1. Given flow rate and fluid properties, calculate Reynolds number and flow regime.
2. Use velocity limits to pick a trial diameter.
3. Compute friction losses (Darcy–Weisbach or Hazen–Williams for water).
4. Add elevation and minor losses.
5. Iterate until the pressure drop and velocity meet design criteria.

Then move to complete network problems (branches, loops, pumps, etc.).

📘 6. Recommended Learning Resources

• Books
• Crane TP-410 – Flow of Fluids Through Valves, Fittings, and Pipe
• Pipe Flow Handbook by Butterworth
• Perry’s Chemical Engineers’ Handbook (sections on fluid flow)
• Pump Handbook (McGraw-Hill)
• Online
• Engineering Toolbox (free charts & examples)
• Khan Academy / Coursera (fluid mechanics refreshers)
• YouTube channels: LearnChemE, Practical Engineering, HVAC School

🧠 7. Get Hands-On

If you’re in industry:

• Observe how your plant or facility engineers specify line sizes.
• Compare system drawings (P&IDs) to real installations.
• Ask about why specific diameters were chosen.
• Try back-calculating flow velocities from known pipe sizes.

If you tell me what type of system you want to size (e.g., steam, condensate, water supply, compressed air), I can walk you through a worked example and even give you a spreadsheet or formula template to start practicing.

I am going to try structural design next!

By the way, I come to mills and talk to various departments about many subjects. To arrange my custom visit to your mill, just email me at jim.thompson@ipulpmedia.com or call me at 678-206-6010.